Stuttgart 2012 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 39: Poster: Atomic clusters

A 39.3: Poster

Donnerstag, 15. März 2012, 16:30–19:00, Poster.V

Observation of single and multiple ionization by electron impact ionization of small noble gas clusters — Thomas Pflüger, Arne Senftleben, Xueguang Ren, •Alexander Dorn, and Joachim Ullrich — Max-Planck-Institut für Kernphysik, 69117 Heidelberg

A kinematically complete experiment for 100 eV electron-impact ionization of small argon and neon clusters was realized. For argon the triple coincidence detection of both outgoing electrons and the residual ion allows the discrimination between single ionization of atoms, dimers and non-mass-selected small clusters as well as between pure ionization and ionization with additional excitation within the same cluster. Comparison of fully differential ionization cross sections for clusters with those of atoms reveals clear signatures of multiple-scattering reactions. For ionization with excitation, an almost isotropic electron emission pattern is observed.
Ionization of dimers and trimers with subsequent Coulomb explosion resulting in two charged fragments shows interisting collisional ionization mechanisms as the interatomic Coulombic decay (ICD) and sequential ionization of two cluster atoms by the projectile.